Spectroscope



I Sept. 28, 1937. T. A. CUTTING SPECTROSCOPE Filed Nov. 8, 1934 YILEInventor Patented Sept. 28, 1937 UNITED STATES PATENT OFFICESPECTROSCOPE Theodore A. Cutting, Campbell, Calif.

Application November 8, 1934, Serial No. 752,093

11 Claims..

Fig. III is a vertical section with, spark apparatus in side elevation,and t Fig. IV is a front view of the double gap.

The spectroscope has a diffraction grating i held in tube 2 by a liningtube,,one part of which 3 is below and the other part 4 above thegrating l. A circular disk 5 closes the bottom of tube 2, and a washer 6partly closes the upper end. Since the rays of light do not passperpendicularly through the grating l, the upper end of tube 2 is cut atan angle of about 45 degrees so that the rays will not be obstructed bythe walls.

A window 1 opens just below the level of the grating I and is narrowedto a slit by the slide 8 held in track 9, fastened longitudinally to theside of the spectroscope by ends clinched over the ends of the tube,Slide 8 may operate in either the upper or lower end of track 9, orthere may be two slides, one above and one below.

In place of a slit between slides 8, a'cylindrical lens of glass l0 maybe substituted. A beam of light striking the curved glass will enter it,be reflected from the inner surface, and again emerge. At certaincritical angles the beam of light will be dispersed into its separatecolors as 40 by a drop of water in a rainbow. As the beam passes throughthe grating I, it is still further dispersed and so produces the desiredspectrum.

.It has been found that glass cylinders of small diameter give fineclear lines where the source of light is strong, and that cylinders ofgreater di: ameter give brighter lines where the source of light isweak. The cylindrical lens Ill is attached to the end of slide H, partof which runs in the grooves of 9 and part l2 of which lies parallel tothe track on the outside. The end of the slide is trifurcated, having ashort middle branch 22 bent at right angles to form a rest for the lens,and having two other branches 23 and 24 encircling the ends of thecylinder of glass and holding it in place. The lens may be criticallyadjusted by sliding it up or down before the window.

For spectrum analysis it is highly desirable to have two spectra side byside for comparison. The double or multiple gap shown in Fig. IV inwhich two different metals are bolted together, as for instance, a stripof copper l4 and a strip of zinc 15, serves this purpose. Strip I6 iscopper and I! zinc. With a spark strong enough to leap both gaps inseries, two spectra are produced side by side for comparison.

Some substances yield better spectra in a low voltage are carrying'arelatively large current than in a high voltage arc with a smallcurrent, but with an alternating current it is often diflicult orimpossible to operate an are between metal electrodes. However, byattaching the substance ill to be examined to the end oi. spring l9vibrated by an electromagnet 20, and allowing a current of two or threeamperes to flow. interruptedly between the'substance l8 and a carbonrod, or other mass of substance 2|, an arc may be produced. Twodissimilar tips side by side may be used for comparative spectra. Therapid vibration gives the appearance of a continuous arc, and thefrequent actual contact of the electrodes maintains the arc.

In another form, the cylinder I0, instead of being of glass may be ofpolished metal to reflect a flat beam of light into the window I, or itmay be of colored glass to select some particular ray. In case thesource of light is a spark, the cylinder may be discarded and in somecases even the slides dispensed with, for when the beam of light isnarrow the grating will disperse it without other assistance.

I claim:

1. A spectroscope having a tubular casing, a diffraction grating withinand athwart said casing, a tubular lining both above and below saidgrating, a track external to said casing and parallel thereto and havingends hooked over the ends of said casing, a window penetrating saidlining, casing, and the bottom of said track just beneath said grating,a slide for said track, a lens mounted upon said slide, said lens havingthe form of a right circular cylinder mounted with its longitudinal axisparallel to the plane of the grating, and a disk closing the bottom endof said casing.

2. A spectroscope having a casing, an opaque closure for one end of saidcasing, a diflraction grating athwart said casing near the open end, awindow in said casing between said opaque closure and said grating andclose to the edge of said 55 grating, a cylindrical lens having itslongitudinal axis parallel to the plane of said grating and mounted uponthe casing at the window in order to direct light therethrough, andmeans for holding said cylindrical lens adjustably in such a position.

3. In combination in a spectroscope, a tubular casing, an opaque closurefor one end of said casing, a diffraction grating athwart the open endof said casing, a window at the edge of said diffraction gratingthroughthe wall of said casing, and a cylinder lens mounted with itsaxis parallel to the plane of said grating at said window.

4. A spectroscope having in combination a tubular casing, a lateralopening in said casing, slides adjustably closing said opening, adiffraction grating athwart said tubular casing, a transparentcylindrical lens mounted upon one of said slides and having itslongitudinal axis parallel to the plane of said grating, tubular meansfor holding said grating within said tubular casing, and a disk closingthe lower end of said casing.

5. A spectroscope having in combination a diflraction grating, a darkchamber beneath said grating, a small window in said chamber justbeneath one edge of said grating, a cylindrical light deflecting bodymounted upon said chamber with its longitudinal axis parallel to theplane of the grating and adjustably placed at said window for directinga beam of light upon said grating at a large angle of incidence,'and ashield above said grating to prevent direct rays of light from strikingthe upper surface of said grating.

6. A spectroscope having a diffraction grating, a chamber beneath saidgrating and attached thereto, a window in said chamber at the edge ofsaid grating, a track upon the exterior wall of said chamber, a slidefor said track, and a cylindrical lens mounted upon said slide with itsaxis parallel to the plane of the grating.

7. A spectroscope having a tubular casing, a

and adapted partly to close said window.

8. A spectroscope having a tubular casing with the bottom out at rightangles and the 'top obliquely, a. closure at the bottom of said casing,a diffraction grating athwart the top, a window in the casing just belowsaid grating, a track mounted longitudinally upon said casing, andslides guided by said track for narrowing the window to a slit parallelto the plane of said grating.

9. A spectroscope having a casing, an opaque closure for one end of saidcasing, a diffraction grating athwart said casing near the open end, awindow in said casing between said opaque closure and said grating andclose to the edge of said grating, and silt defining means producing aslit parallel to the plane of said grating, ad- Justably mounted uponsaid casing and partly closing said window.

10. A spectroscope having in combination a difiraction grating and acylindrical lens with its axis parallel to the plane of said grating andmounted at the edge of said grating for directing light thereupon.

11. A spectroscope having a casing, an opaque disk at the bottom of saidcasing, a tube within said casing resting upon said disk, a diffractiongrating athwart said casing resting upon said tube, a track memberexternal to said casing and longitudinal therewith with ends bent overthe extremities of said casing, a window penetrating said tube, saidcasing, and said track, and slides operating in said track and partiallyclosing said window.

THEODORE A. CUTTING.

